Improved Performance of All‐Polymer Solar Cells Enabled by Naphthodiperylenetetraimide‐Based Polymer Acceptor

TLDR

The authors designed and incorporated a novel naphthodiperylenetetraimide‑vinylene polymer acceptor (NDP‑V) into all‑polymer solar cells. NDP‑V was engineered to reduce backbone conformational disorder relative to the earlier PDI‑V acceptor, yielding tighter molecular packing, improved donor‑acceptor morphology, and stronger short‑wavelength absorption. These structural improvements enabled all‑polymer solar cells to reach a record power‑conversion efficiency of 8.59 % (average 8.48 %) with a short‑circuit current density of 17.07 mA cm⁻² and a fill factor of 0.67, the highest reported for this class.

Abstract

A new polymer acceptor, naphthodiperylenetetraimide-vinylene (NDP-V), featuring a backbone of altenating naphthodiperylenetetraimide and vinylene units is designed and applied in all-polymer solar cells (all-PSCs). With this polymer acceptor, a new record power-conversion efficiencies (PCE) of 8.59% has been achieved for all-PSCs. The design principle of NDP-V is to reduce the conformational disorder in the backbone of a previously developed high-performance acceptor, PDI-V, a perylenediimide-vinylene polymer. The chemical modifications result in favorable changes to the molecular packing behaviors of the acceptor and improved morphology of the donor-acceptor (PTB7-Th:NDP-V) blend, which is evidenced by the enhanced hole and electron transport abilities of the active layer. Moreover, the stronger absorption of NDP-V in the shorter-wavelength range offers a better complement to the donor. All these factors contribute to a short-circuit current density (J sc ) of 17.07 mA cm-2 . With a fill factor (FF) of 0.67, an average PCE of 8.48% is obtained, representing the highest value thus far reported for all-PSCs.